This invention is generally directed to toner and developer compositions, and more specifically, the present invention is directed to developer and toner compositions containing a tribofiller which imparts or assists in imparting charge to the toner resin particles and enable toners to be formulated with dissimilar passivated pigments irrespective in embodiments of the pigment volume selected. There are provided in accordance with the present invention toner compositions comprised of resin particles, passivated pigment particles, and tribofillers to enable toners with relatively constant triboelectric charging characteristics irrespective of the passivated pigment loading. In one embodiment, the present invention is directed to toners with known pigments, like cyan, magenta, yellow, red, blue, green, black, mixtures thereof, and the like and certain tribofillers which are added to the toner. The toner pigments selected can be passivated with a polymeric coating. The tribofillers can be comprised, for example, of passivated finely compounded materials selected on the primary basis that they are transparent in the visible region of the spectrum and that they have nearly the same, or identical index of refraction as that of the toner resin. The tribofillers can also be passivated with the polymeric coating selected to passivate the toner pigment. A constant triboelectric series of materials can be designed for several different pigments which utilize different concentrations by assuring a constant volume fraction of pigment and tribofiller in the toners thereof. The toner and developer compositions of the present invention can be selected for electrophotographic, especially xerographic, imaging and printing processes, including color processes.
Toners with passivated pigments include those comprised of known toner resins, colored pigments, such as red, blue, green, cyan, magneta, yellow, or mixtures thereof, and wherein the pigment is passivated, or rendered substantially inactive with respect to the adverse electrical effects that are imparted to the toner. Passivated pigments and processes thereof are disclosed, for example, in copending patent applications U.S. Ser. No. 705,995, U.S. Pat. No. 5,208,129 and U.S. Pat. No. 5,212,035 the disclosures of which are totally incorporated herein by reference.
In a patentability search report there was recited as background interest U.S. Pat. Nos. 4,937,167; 5,023,161; 4,524,203 and 4,291,112.